Impact Identification of Carbon-Containing Carboniferous Clays on Surfaces of Friction Nodes

The article deals with issues related to the processes occurring in the wear result of steel surfaces of machine components in the presence of mineral grains. This type of destruction of cooperating surfaces usually takes place during the development of roadways or during mining of coal with use of longwall methods. Wear tests were carried out using the author’s ring-on-ring test stand, on which the conditions of real wear of machine components in the presence of rocks were simulated. An abrasive material based on clayey rocks with an admixture of carbonaceous substance was used in the tests. Based on the analyses, it was found that the obtained results related to the damages are typical for wear mechanisms: microcracking and low-cycle fatigue. On the surface of the steel samples, numerous effects of micro-cutting and chipping could be observed, which were the result of the clayey impact of wear products and grains of the mineral substance. Under friction, a part of the abrasive and the carbon substance were pressed into generated microcracks, which is directly related to their plastic properties. The remaining, unpressed part of the abrasive material was subjected to further friction effects caused by the pressure of the tester pocket load and the relative movement of both steel rings surfaces. After the friction tests, the mixture of silty carbon abrasive material was in the form of flat aggregates on the samples’ surfaces.